The invention relates to a sheet transport cylinder in a machine that processes sheets of printing material. The sheet transport cylinder has air nozzles for sheet formats of the printing-material sheets that are dimensioned from a minimum format up to a maximum format, according to the preamble of claim 1.
German Published, Non-Prosecuted Patent Application DE 43 15 527 A1, corresponding to U.S. Pat. No. 5,542,659 to Haupenthal, includes a description of a sheet transport cylinder whose air nozzles are assigned a multi-way shut-off slide for adapting the format. The slide is capable of being operated manually or of being coupled to a drive device that is driven by a central machine control system.
The drawback with the prior art device is the expenditure of time that is needed in changing the format and that, in the case of manual operation, is needed for changing the format and, in the case of being driven by the machine control system, is needed for monitoring the changing of the format.
It is accordingly an object of the invention to provide a sheet transport cylinder that overcomes the hereinafore-mentioned disadvantages of the heretofore-known devices of this general type and that provides a sheet transport cylinder with a less complicated format changeover.
With the foregoing and other objects in view, in a machine processing sheets of printing material having various sheet formats, there is provided, in accordance with the invention, a sheet transport cylinder includes throttled air nozzles for affecting printing-material sheets having various size sheet formats. The sheet formats are dimensioned from a minimum format to a maximum format. The throttled air nozzles are disposed to match the minimum format.
Throttled air nozzles are surrounded by the air nozzles and are disposed such that they are matched to the minimum format. Therefore, all or at least some of the air nozzles of the sheet transport cylinder are throttled. In other words, some of the air nozzles of the sheet transport cylinder are throttled and some are unthrottled.
One advantage of the sheet transport cylinder according to the invention is that when the cylinder is being changed over to smaller sheet formats, no air shut-off measures relating to the volume of flow through the throttled air nozzles are needed, because of the low volume flow.
In accordance with another feature of the invention, there are provided air nozzles in addition to the throttled air nozzles. The air nozzles include unthrottled air nozzles.
In accordance with a further feature of the invention, the throttled air nozzles are disposed at points on a peripheral surface of the sheet transport cylinder that are not covered by the minimum format. The throttled air nozzles are, therefore, disposed downstream of a trailing edge and/or beside a side edge of the minimum format transported by the sheet transport cylinder.
In accordance with an added feature of the invention, only throttled air nozzles, and no unthrottled air nozzles, are located outside a region of the peripheral surface of the sheet transport cylinder that is covered by the minimum format. If the throttled air nozzles are suction nozzles, the embodiment minimizes the extraneous air stream flowing in through the uncovered, throttled air nozzles into an air line system belonging to the sheet transport cylinder, so that the vacuum prevailing in the air line system remains substantially functionally unimpaired. If, however, the throttled nozzles of the embodiment are blown air nozzles, then an extraneous air stream flowing out of the air line system through the uncovered, unthrottled nozzles is minimized. Accordingly, the consumption of energy required to generate the blown air, and the noise nuisance caused by the extraneous air, are reduced.
In accordance with an additional feature of the invention, the unthrottled air nozzles are covered by the minimum format. For example, within the area of the peripheral surface that is covered by the minimum format, only unthrottled air nozzles and no throttled air nozzles can be disposed. However, both throttled air nozzles and unthrottled air nozzles can be disposed within the area of the peripheral surface.
In accordance with yet another feature of the invention, the unthrottled air nozzles are disposed within the peripheral surface area.
In accordance with yet a further feature of the invention, an air throttle is associated with at least one of the throttled air nozzles.
In accordance with yet an added feature of the invention, each of the throttled air nozzles is connected to an air pressure generator through an air throttle. The air throttle can be integrated into the air line system remotely from the respectively throttled air nozzle. The configuration is beneficial if an air throttle is provided that, through the air line system, is simultaneously pneumatically connected to a plurality of throttled air nozzles. The air throttle and the air nozzle throttled by the air throttle can also form one structural unit in the form of a throttled nozzle. In such a case, each of the throttled air nozzles (throttled nozzles) is associated with its own air throttle disposed in the air nozzle (throttled nozzle).
In accordance with yet an additional feature of the invention, a bulk filling column is located in the air throttle as its constituent part, its small bulk elements forming flow resistances for the suction or blown air flowing through the air throttle and generated by the air pressure generator.
In accordance with again another feature of the invention, a throttling piece like an air filter is located in the air throttle as a constituent part and forms a flow resistance for the suction or blown air. For example, the throttling piece is a textile layer that may be woven or non-woven. However, the throttling piece can also be a porous and, therefore, air-permeable sponge, which has been foamed from a plastic.
In accordance with again a further feature of the invention, the air throttle is a spiral air duct.
In accordance with again an added feature of the invention, the air throttle is occupied by air baffles that project into the flow path of the suction or blown air and bound eddy chambers disposed between the projecting air baffles.
In accordance with again an additional feature of the invention, the air throttle is a perforated plate labyrinth.
In accordance with still another feature of the invention, the air throttle includes perforated plates disposed one above another and eddy chambers disposed between the perforated plates.
In accordance with still a further feature of the invention, the throttled air nozzles are suction nozzles.
In accordance with still an added feature of the invention, the throttled air nozzles are blowing nozzles.
With the objects of the invention in view, there is also provided a sheet-fed rotary printing machine processing printing-material sheets including at least one sheet transport cylinder having throttled air nozzles for affecting printing-material sheets having various size sheet formats, the sheet formats dimensioned from a minimum format to a maximum format, the throttled air nozzles disposed to match the minimum format.
Other features that are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a sheet transport cylinder, it is, nevertheless, not intended to be limited to the details shown because various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.